This invention relates generally to percutaneous electrical therapy systems for medical use. In particular, the invention relates to an electrode introducer for inserting percutaneous electrodes.
Electrical therapy has long been used in medicine to treat pain and other conditions. For example, transcutaneous electrical nerve stimulation (TENS) systems deliver electrical energy through electrode patches placed on the surface of a patient""s skin to treat pain in tissue beneath and around the location of the patches. The efficacy of TENS systems in alleviating pain is questionable at best, however.
More recently, a technique in which electrodes are placed through the patient""s skin into the target tissue has been proposed. Percutaneous Neuromodulation Therapy (xe2x80x9cPNTxe2x80x9d) (also sometimes called Percutaneous Electrical Nerve Stimulation or xe2x80x9cPENSxe2x80x9d) using percutaneously placed electrodes achieves significantly better pain relief results than TENS treatments using skin surface electrodes. This therapy is described in Ghoname et al., xe2x80x9cPercutaneous Electrical Nerve Stimulation for Low Back Pain,xe2x80x9d JAMA 281:818-23 (1999); Ghoname et al., xe2x80x9cThe Effect of Stimulus Frequency on the Analgesic Response to Percutaneous Electrical Nerve Stimulation in Patients with Chronic Low Back Pain,xe2x80x9d Anesth. Analg. 88:841-6 (1999); Ahmed et al., xe2x80x9cPercutaneous Electrical Nerve Stimulation (PENS): A Complementary Therapy for the Management of Pain Secondary to Bony Metastasis,xe2x80x9d Clinical Journal of Pain 14:320-3 (1998); and Ahmed et al., xe2x80x9cPercutaneous Electrical Nerve Stimulation: An Alternative to Antiviral Drugs for Herpes Zoster,xe2x80x9d Anesth. Analg. 87:911-4 (1998). The contents of these references are incorporated herein by reference.
Thus far, PNT practitioners have used percutaneously placed acupuncture needles attached to waveform generators via cables and alligator clips to deliver the therapy to the patient. This arrangement and design of electrodes and generator is far from optimal. For example, insertion of percutaneous electrodes has thus far been cumbersome and inaccurate. It is therefore an object of this invention to provide an improved percutaneous electrode introducer.
It is a further object of this invention to provide a percutaneous electrical therapy system having electrodes and electrode assemblies that are safe, efficacious, inexpensive and easy to use.
Other objects of the invention will be apparent from the description of the preferred embodiments.
The invention is a percutaneous electrode introducer, such as for use with a percutaneous electrical therapy system. In a preferred embodiment, the percutaneous electrode introducer includes a housing adapted to be held in a user""s hand, the housing having an aperture at a distal end; an electrode disposed in the housing, the electrode having a sharp point at a distal end; and an actuator adapted to be operable by a user to move the electrode through the aperture and completely out of the housing to place the sharp point of the electrode beneath a patient""s skin.
In some embodiments, the electrode may have an electrical connector portion at a proximal end, the actuator being further adapted to place the sharp point of the electrode beneath the patient""s skin with the electrical connector portion of the electrode being exposed above the patient""s skin.
In some embodiments, the actuator is further adapted to be operated by a user""s thumb to move the electrode through the aperture.
In some embodiments of the invention, the introducer also has a transmission assembly adapted to move the electrode""s sharp point a first distance when the actuator is moved a second distance, the second distance being less than the first distance.
In one particular embodiment, the introducer has a plurality of electrodes, the actuator being operable by the user to move each of the plurality of electrodes individually through the aperture and completely out of the housing to place the sharp point of each electrode beneath a patient""s skin. This embodiment may have a magazine in which the plurality of electrodes is disposed, and the magazine may have a plurality of electrode chambers.
In some embodiments, the introducer""s aperture is adapted to cooperate with an alignment element to align the introducer with an electrode insertion site.
In some embodiments, the introducer""s actuator and electrode are adapted to move in the same direction during placement of the sharp point of the electrode beneath the patient""s skin.
In some embodiments, wherein the introducer has a longitudinal axis, the actuator and the electrode being adapted to move along, or parallel to, the longitudinal axis during placement of the sharp point of the electrode beneath the patient""s skin.
The invention is described in further detail below with reference to the drawings.